Time-varying wireless networks covering significant distances, such as low and medium earth orbit satellite constellations, deep space/interplanetary networks, airborne networks, and underwater networks present a series of challenges for reliable and secure communications including intermittent connectivity, long and/or variable delay, asymmetric data rates, and high bit error rates. These problems arise due to factors such as orbital movement, atmospheric interference, high latitudes and challenging planetary terrain, and distance between objects in space. For example, the travel time for electromagnetic radiation between Earth and Mars can vary from about 4 minutes to approximately 24 minutes depending on their relative orbital positions. Accordingly, there is a need for a system and method for communications that overcomes these problems.